OBJECTIVE: To investigate platinum compounds for their selective toxicities on murine plasmacytomas and, thus, for their potential therapeutic efficacy in human multiple myeloma. The quantitation of their differential effects on murine plasmacytoma and hemopoietic stem cells will be carried out using clonal cell culture techniques for each class of cells. Results seen in culture assays are to be confirmed by survival experiments in mice carrying transplantable plasmacytomas. To investigate the mechanism of action of the effective platinum compounds. Initial emphasis will be placed on the studies of their cell cycle dependency and modes of transport. The investigation will include human bone marrow precursor cells as well as murine plasmacytoma and hemopoietic precursor cells. To investigate the antitumor effect of cis-diamminedichloroplatinum (NSC 119875) in patients with multiple myeloma who have become refractory to conventional chemotherapy.